This invention relates generally to electric cigar lighters of the type employed in automobiles or other motor vehicles, and more particularly to lighters of the type incorporating a socket part that is mounted in a dashboard or other panel, and a removable plug part that carries an electric heating element.
Many different constructions involving electric cigar lighters of the above type have been developed over the years. Generally, the socket of the lighter device had an out-turned flange or bezel at its front, and was inserted through a hole in the dashboard or panel, being held captive therein by a tubular clamping shell that was screwed onto the socket from the rear, behind the dashboard. The front edge of the clamping shell engaged the rear surface of the dash, and held the socket in position. That is, the dashboard or panel was sandwiched between the out-turned flange of the socket and the front edge of the clamping shell.
Most of the older model automobiles employed metal panels, and thus one part of the cigar lighter circuit was established from the metal part of the socket to the panel and ground. With the advent of newer car models involving both cost and weight reduction, plastic panels and bezels are now being employed to a far greater extent. This generally necessitates the use of a grounding terminal or lug of some type, in electrical contact with the metal shell or body part of the socket. Previously, the electrical contact to this part was made by means of a spade lug that was welded to the clamping shell, and which was received in a cooperable grounding terminal from the vehicle electrical system. Since the clamping shell, being consitituted of metal, was in electrical contact with the socket, there existed the required continuity for the ground circuit.
Several problems have occured, however, with regard to the welding of a lug onto the clamping shell, the most important including lack of a reliable test for integrity of the weld, and failure of the weld at some time during the subsequent life of the component or shell. Generally both the socket and shell are plated in order to avoid deterioration from moisture, particularly where the devices are disposed in the arm rests of the doors of the vehicle. Often these devices would become wet if a window of the vehicle was inadvertently left open during a storm, or where the vehicle was exposed to a corrosive industrial or salt atmosphere. In the past, when it was required to fasten an electrical connector in the form of a spade lug to the clamping shell, it has been customary to plate the part after the fastening operation, since the welding disturbed any pre-existing plating. But, under any circumstance, the welding step was time consuming, involving manual labor, and this, as well as the plating of finished parts, represented an additional expense. With the impact of the continually rising labor costs represented by the above, the clamping shell started to become a product that was cost-prohibitive and no longer economical to produce in the environment of the electrical cigar lighter.